Mounting element and method of attachment to glass



Oct. 10, 1961 v. PFAENDER 3,004,182

MOUNTING ELEMENT AND METHOD OF ATTACHMENT T0 GLASS Filed March 15, 1958 Y #2 Z0) 7 x12 X L J4 4 T TORNQYS 3,004,182 MOUNTING ELEMENT AND METHOD OF ATTACHMENT TU GLASS Lawrence V. Pfaender, Toledo, Ohio, assignor to Owenslllinois Glass Company, a corporation of Ohio Filed Mar. 13, 1958, Ser. No. 721,305 9 Claims. (ill. 31364) This invention relates to lug or stud-like elements and the method of attachment of such elements to the Walls of glass articles, and in particular to a specific structure for such elements whereby certain difliculties encountered in their use and mounting may be eliminated.

Previously in conventional mounting or inserting of log or stud elements in and/or through a glass wall, the only problem encountered has been the difference in thermal expansion and contraction as between the material of the element and the glass. An example of such element is an anode button employed as an electrical terminal in the wall of a glass cathode-ray picture tube in a normal monochrome television set. Such buttons are comprised of a material which is conductive and which has thermal expansion and contraction characteristics compatible with those of the glass member.

In'the production of polychromatic type tubes it has been found desirable or necessary in certain types of these tubes to mount a large color-controlling element in close proximity to the tube viewing area to control electron impingement upon prescribed areas of a luminescent screen, for example. The color-controlling element may consist of an apertured electrode member which is designed to permit alternating shielding of certain portions of the screen while other portions are bombarded with electrons.

The development of color television picture tubes has been hindered by the stringent requirements of precise alignment of internal components, particularly the colorproducing electronic elements mounted within the face plate portion of the tube. In present practice, an apertured electrode structure such as a shadow mask or line grid is usually disposed adjacent the tube screen to control electron impingement upon luminescent phosphors capable of developing three primary colors. The electrode structure frequently consists of a rather heavy frame and complicated and bulky clamping mechanism all of which add to the difiiculty of tube assembly and exhaust while maintaining the required alignment. The precise location of the apertured electrode must be carefully controlled with respect to the phosphor screen during its stepwise deposition so that each individual tube is capableof maintaining proper color registry. Usually the electrode must be installed and removed several times during creation of the screen, each re-installation being in an exacting duplicatable position.

Previously, especially contoured areas of the glass face plate such as glass studs have been employed to contact and hold the frame portion of the large mask or grid. Difliculty has been experienced when the tube is subjected to physical or thermal shock to the extent that this form of mounting has largely been considered unacceptable in practice. The contoured areas of the glass sometimes tend to become chipped or fractured where hard metals such as stainless steel alloys are permitted to directly contact the glass. As a result the intermediate mask or grid may be displaced out of alignment with the electron-emitting source or sources and the oppositelydisposed target area of the tube viewing window rendering the tube defective. The metal alloy being of greater hardness than the glass tends to score the latter creatingareas of weakness which tend to reduce tube life. 7

Accordingly, it is an object of this invention to provide an improved supporting structure for a demountable electronic element of considerable size positioned in positive alignment on the inside of a hollow article such as television tube of the chromatic-type.

Another object of this invention is to provide a novel support bracket for use in series to support a large electron-beam controlling element in precise demountable arrangement within a cathode-ray tube envelope, which bracket is adapted to be thermally sealed to glass without adverse effects thereon and has normally difficult to grasp mounting surfaces for the electronic element.

Another object of this invention is to provide a glass face plate member for a cathode-ray tube envelope having an integral series of lug elements sealed interiorly of its peripheral flange for retaining a detachable color-controlling member in precise arrangement.

A further object of this invention is the provision of a frangible component element for attachment in series to ship with'respect to the viewing area of the face plate.

member, the method comprising simple steps applicable to existing and proposed types of chromatic television picture tubes.

The specific nature of this invention, as well as other objects and'advantages thereof; will become apparent to those skilled in the art from the following detailed description, taken in conjunction with the annexed sheet of drawings on which, by way of preferred example only, are illustrated the preferred embodiments of this invention.

On the accompanying drawings:

FIG. 1 is a fragmentary vertical sectional view of a glass face plate member embodying the present invention.

FIG. 2 is an enlarged vertical sectional view of one portion of FIG. 1 illustrating a portion of jig mechanism for attaching one or more stud elements to the face plate.

FIG. 3 is a view similar to FIG. 2 illustrating the frangible nature of the stud member in finally disposed relationship.

Although this invention will be described as specifically applied to the manufacture of a cathode-ray tubeand its glass viewing portion in particular, it will be apparent to I those skilled in the art that the principles of the invention are equally applicable to the manufacture of any type or structure of preformed rigid glass article upon orwithin which it is desired tomount an independent member of substantial size directly supported by studs or brackets attached to the glass in exact relationship therewith.

A preferred embodiment of this invention consists of aglass face plate 10 having a uniformly curved viewing panel 11 and an annular skirt or flange portion 12 which terminates in an annular sealing surface 13. Face plate 10 may be either circular or rectangular in overall configuration and viewing panel 11 may be either cylindrically or concavo-convexly curved as desired or required.

The interior surface of viewing panel 11 constitutes a target or screen area 14 which hasdeposited thereon a layer of phosphor materials which constitutes the imageproducing area of a cathode-ray picture tube. Of course, the particular phosphor materials may be varied widely as known in the art and do not constitute a part of this invention. A face plate fabricated in accordance with the illustrated embodiment is generally similar to that used Patented Oct. 10, 1961 I as an end closing part for a monochromatic tube envelope and alsomay conveniently be employed in the manufacture of a picture tube for chromatic television reception.

In certain common types of color picture tubes it is required to mount a large apertured electrode structure 20 such as a shadow mask or line grid shown in broken lines in FIG. 1. As stated, this structure must be located in extremely precise alignment between although adjacent to screen area 14 and one or more electron-emitting beam guns disposed in the neck portion of the tube funnel (not shown). Structure 2d may consist of a thin perforate metal sheet Zfla extending essentially throughout the viewing area a prescribed constant dimension therefrom, the sheet being attached to a relative stiff peripheral member or frame. The structure 20 is commonly supported in demountable arrangement within the face plate by an angularly spaced series of leaf springs attached to its frame, the springs having openings adapted to snap over a series of mounting posts or stud 15.

It has been found that the physical dimensions of a pre ferred form of structure 20 applicable to employment in a 2.2 inch circular or rectangular color television face plate has necessitated the present invention of mounting studs 15 and their method of attachment. The subject studs have seating surfaces 15b which are frusto-conical in shape. The required accuracy of their placement in the glass has required jig mechanism 16 to grasp and release the studs during their insertion.

The tapered seating surface 15b or so-called nose portion of each stud 15 has made the use of jig collets for their installation particularly difficult. To overcome this each of the studs 15 has a hollow disk-shaped mounting portion 15a having converging side walls which may be easily inserted into the heat-softened glass 12a of the flange. Stud 15 has a tapered seating portion 15b which projectsv beyond the glass surface of lesser maximum diameter than the base or mounting portion 15a. A grasping portion 150 comprising a right-angled cylinder is formed integral and coaxial with the tapered seating portion 15b interconnected by a frusto-conical shaped neck 15a. Neck 15d furnishes a break-off region which facilitates separation of the grasping portion 150 after the stud is properly mounted.

Adequate accuracy of lug placement is almost entirely dependent upon the length of the break-E section. The dimension from the inner end of the stud nose or seating portion b to the end of the frangible grasping section 150 is one which is precisely controlled in the preparation of the parts. Also the degree of taper of seating surface 1512 must be controlled within prescribed limits for receiving resilient spring elements having exact openings.

The contour of break-01f portion 15c which is separated from the stud in finally sealed relationship is important. The diameter of the cylindrical region of the break-off section is sufficiently large to permit easy grasping of the stud within a collet 18, and except for the neck portion 15d, is ofthe same diameter as the base of the tapered seating portion 1511. This contour facilitates fabrication of the studs by screw making machines. The neck portion between the break-off section and the stud nose is frusto-conically shaped in the opposite direction so that the smallest diameter occurs at the innermost termination of seating portion 15b. This area may have a dimension of less than 0.25 inch diameter and in any event is snfliciently strong to permit installation of the stud 15 into the glass without bending.

The method of installation is as follows:

The face plate is preferably preheated in a heating chamber or lehr to a temperature of about 400 F. or above. Localized surface areas of the flange 12 are then heated into workable condition with gas flames, for example, to a temperature of nearly 2100" F. over a relatively short period of time so that distortion of flange contour particularly its exterior and sealing surfaces 13 does not occur. Either interior surfaces alone or oppositely disposed interior and exterior surfaces may be heated to the stated high temperature. After the prescribed areas such as a triangular pattern are sufiiciently heat-softened, the burners are withdrawn and a jig assembly 16 of lesser size than flange 12 is inserted within the face plate in a position a prescribed dimension X from the screen area 14. A series of three studs 15 are retained within the perimeter 17 of the jig assembly a prescribed arcuate distance Y from each other. In the case of a triangular stud arrangement two studs may be placed apart with the angles between the third being Obviously, this pattern may be modified widely although it is preferred to use unequal angles between one pair of studs so that only a single aligned position is possible therebetween.

The studs 15 are retained Within collets 1% in retracted position and following proper location of the jig 17, the collets are simultaneously driven outwardly a prescribed distance so that the base portion 15a of each stud is partially embedded within the softened glass 12a. Heating may be continued at this time. Each collet 18 may have an adjustable central pin 19 to secure more accurate positioning of individual studs. As shown in FIG. 2, the outer surface of base portion 15a is seated by the outermost face of collet 13.

After the studs are inserted into the glass the jig is maintained in the precise permanent arrangement desired during subsequent cooling of the glass to either a lower setting temperature or room temperature. During the cooling of the glass, the dissipating heat is conducted through the neck portion 15d of each stud and this area tends to become rather brittle due to grain growth of the metal. After the glass is fully cooled the collets 18 and their housing members 17 are withdrawn interiorly of the inner limit of the respective studs and the jig removed from the face plate. The frangible portions of each stud may then be separated from the seating portion 15b by mechanical twisting action to eifect a separation at the neck portion 15d.

The neck portion of the break-off section serves as a thermal barrier to reduce heat transfer to the retaining collets in the thermal sealing of the studs to the glass. This region serves to resist heat flow into the positively retained grasping separable portion 15c and permits the mounting portion 15a to become more readily heated to facilitate joinder to the glass.

The stud elements 15 may be composed of stainless steel and particularly titanium stabiiized No. 430 stainless steel is preferably employed in fabricating the metallic studs. This alloy has expansivity and thermal conductivity properties which make it especially useful for scaling to certain electronic glasses.

Various modifications may be resorted to within the spirit and scope of the appended claims.

I claim:

1. A load-supporting stud element for utilization with a preformed glass part or article comprising a cylindrical metallic member having a hollow disk-shaped mounting portion adapted to be sealed partially beneath a glass surface, a frusto-conical portion adapted to extend beyond the glass surface comprising a seating surface for an electronic element, and a frangible portion extending beyond said frusto-conical portion adapted to facilitate precision mounting of said member partially within the glass prior to its elimination and subsequent mounting of said electronic element.

2. A load-supporting stud element for utilization in the manufacture of a glass face plate of a cathode-ray tube envelope comprising a cylindrical member comprised of metallic alloy having thermal properties in suitable agreement for scaling to said face plate, said member having a disk-shaped hollow mounting portion with converging sidewalls adapted to be sealed partially beneath the glass surface, a frusto-conical portion of lesser diameter than said mounting portion adapted to extend beyond the glass surface to provide a precisely-located seating surface for an electronic color-controlling element, and a frangible portion extending in axial alignment with and beyond said frusto-conical portion adapted to permit precise mounting of the stud element with respect to prescribed areas of the face plate.

3. A load-supporting stud element for attachment to a glass face plate of a cathode-ray tube envelope comprising a cylindrical member consisting of a metallic alloy having physical properties in suitable agreement for thermal sealing to said glass face plate, said member having a disk-shaped hollow mounting portion with converging sidewalls adapted to be sealed partially beneath the glass surface, a frusto-conical portion of lesser diameter than said mounting portion adapted to extend beyond the glass surface to provide a precisely-disposed seating surface for an electronic color-controlling element, a right-cylindrical grasping portion extending beyond said frusto-conical portion adapted to permit precise retention of the stud element during its attachment to the glass, and a frangible neck portion interconnecting said frusto-conical seating and right-cylindrical grasping portions for elimination of the latter.

4. A face plate member for a cathode-ray tube envelope comprising a hollow disk-shaped enclosing part having a viewing portion and a surrounding flange portion, a series of at least three metallic stud-like elements mounted in spacedapart relationship interiorly within the flange portion, each of said elements having a cylindrical shape with a hollow disk-shaped mounting portion at least partially embedded within the glass or" said flange portion and an inwardly-projecting seating portion extending from the flange surface adapted to retain a color-controlling electronic element within said face plate.

5. The face plate member for a cathode-ray tube envelope in accordance with claim 4, each of said stud-like elements comprised of a metallic alloy adapted to be thermally sealed to glass and a frusto-conical shaped seating surface for retaining a color-controlling electronic element in precise alignment with the viewing portion.

6. The face plate member for a cathode-ray tube envelope in accordance with claim 4, each of said stud-like elements having an internally extending coaxial frangible portion connected to said frusto-conical seating portion for precision mounting of each element with respect to the viewing portion of the face plate.

7. The method of attaching a series of metallic stud-like elements to the flange portion of a glass face plate of a cathode-ray tube envelope in alignment with its viewing area, said method comprising the steps of heating localized surface areas of the flange portion to near their softening point temperature, retaining a plurality of stud-like elements in precise arrangement within a jig assembly disposed within said face plate, radially ejecting said studlike elements a prescribed distance to partially embed their base portions within the heat-softened areas of the flange portion, allowing the glass to cool, removing said jig assembly from the face plate, and separating frangible grasping portions of said elements leaving precisely-located seating surfaces for an electronic member interiorly exposed.

8. The method of attaching a series of metallic studlike elements to the flange portion of a glass face plate of a cathode-ray tube envelope in accordance with claim 7, including the step of precisely locating the jig assembly with respect to the viewing area of said face plate prior to the insertion of three stud-like elements in triangular arrangement Within said flange portion.

9. The method of attaching a series of metallic studlike elements to the flange portion of a glass face plate of a cathode-ray tube envelope in accordance with claim 7, including the step of retaining each stud-like element in said jig assembly by a frangible cylindrical portion during its mounting in said flange and separating the frangible portion of each element at a neck region by mechanical action prior to installing the electronic member.

References Cited in the file of this patent UNITED STATES PATENTS 2,709,872 Slomski June 7, 1955 2,727,172 Mark Dec. 13, 1955 2,768,475 Seelen Oct. 30, 1956 2,793,319 Nunan May 21, 1957 2,795,719 Morrell June 11, 1957 2,806,162 McQuillen Sept. 10, 1957 2,813,213 Cramer Nov. 12, 1957 2,846,608 Shrader Aug. 5, 1958 FOREIGN PATENTS 742,565 Great Britain Dec. 30, 1955 

